Wherever your deck changes elevation you will need to pay special attention to how the respective levels are supported and attached to one another.  It is usually best to frame one level first to provide a reference to the others.  Sometimes you may need to block in the bottom of a framing member of an upper deck to obtain a positive connection and a smooth transition to a lower section. 

When deck forms of different elevations intersect it is sometimes practical to frame them in a simplified manner and install a platform over the top of the lower deck to create the appearance of a more complex form.  This can be an effective framing technique for an octagon stepped down from an upper section.  You can simplify the framing and eliminate some footings by building a square back to the higher deck and installing small platforms on top of the lower deck to complete and define the shape.